Behavior of post-tensioned fiber concrete beams

Elsharkawy, Hossam-eldin Abd-elazim; Elafandy, Tamer; EL-Ghandour, Abdel Wahab; Abdelrahman, Amr

doi:10.1016/j.hbrcj.2013.08.006

Cited by 11 publications

(4 citation statements)

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“…Uncertainties related to flexural capacity model have been taken into account while neglecting those related to shear capacity, because the latter has minor effect on the overall deck capacity under traffic loads. 25 According to experimental data from the literature, [39][40][41][42][43] 16 PC beams were considered in terms of experimental flexural capacity compared to its theoretical counterpart provided by Equation (1). The model error θ was defined as the ratio between the experimental and theoretical strength values for each specimen, 33 namely θ = M r,exp /M r,th .…”

Section: Discussion Of Resultsmentioning

confidence: 99%

Fragility analysis of existing prestressed concrete bridges under traffic loads according to new Italian guidelines

Miluccio

Losanno

Parisi

et al. 2022

Structural Concrete

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After the 2018 collapse of Morandi highway bridge in Genova, new Italian guidelines (GL) were issued for prioritization of safety evaluations and retrofit interventions on existing bridges. Among several novelties, GL introduced new traffic load models (TLMs) which can be adopted for existing bridges in case of noncompliant safety checks according to the Italian building code (NTC) provisions. In this study, a class of simply supported, beam-type, prestressed concrete bridge decks built between 1970 and 1980 in Italy is considered. Assuming geometric, material, and load random variables together with consideration of capacity model uncertainty, Monte Carlo sampling technique was implemented in MATLAB in order to randomly generate deck models and to evaluate their traffic-load fragility. Fragility analysis was carried out to compare vulnerability levels of existing Italian bridges under different load patterns provided by GL and NTC. In addition to a prescribed TLM, the sensitivity of fragility to bridge usage limitations, such as reduced distance of external load lane from kerb or reduced number of lanes, was also quantified to support decision-making by road management companies. In the final part of the study, the annual failure probability of selected bridges was estimated using a European weigh-in-motion database and convolution of fragility and hazard.Abbreviations: A sp , prestressing steel area; A s , reinforcing steel area; b w , girder web width; CoV, coefficient of variation; d, distance of reinforcing steel rebar from the top compression side; DCR, demand capacity ratio; f ct , concrete tensile strength; FORM, first order reliability method; GL, Italian technical Guidelines for safety assessment of existing bridges; GVW, gross vehicle weight; IM, intensity measure; LRFD, load-resistance factor design; M r , flexural capacity; M r,exp , experimental flexural strength; M r,th , theoretical flexural strength; n l , number of notional lanes; N sim , number of simulations; NTC, Italian building code; P[C], failure probability; P[CjH], conditional probability of exceeding ultimate limit state given intensity measure; P[H], traffic-related hazard; PC, prestressed concrete; PSD, permissible stress design; Q 1d , design first-lane tandem load; R 2 , coefficient of determination; RC, reinforced concrete; r l , remaining area of the carriageway width; RV, random variable; TLM, traffic load model; t ref , residual service life; ULS, ultimate limit state; V r , shear capacity; WIM, weigh-in-motion; x 0 , clear distance of the first notional lane from the kerb; β, logarithmic standard deviation; β 0 , target reliability; β al , logarithmic standard deviation associated with aleatory uncertainties; β ep , logarithmic standard deviation associated with epistemic uncertainties; μ, mean value; σ cp , average compressive concrete stress; σ sp , residual prestressing action; θ, model error.Discussion on this paper must be submitted within two months of the print publication. The discussion will then be published in print,...

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Section: Discussion Of Resultsmentioning

confidence: 99%

Fragility analysis of existing prestressed concrete bridges under traffic loads according to new Italian guidelines

Miluccio

Losanno

Parisi

et al. 2022

Structural Concrete

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“…Also crack sizes and spacing get lessened. Steel fi bers reduce the congestion of reinforcement without affecting the strength aspect (9).Structural integrity of concrete elements, is maintained when fi bers are used in blended form (10). Effi ciency of basalt fi ber in the improvement of the mechanical properties of concrete, is proved in the literature.…”

Section: Introductionmentioning

confidence: 99%

“…Włókna stalowe zmniejszają zagęszczenie zbrojenia, bez wpływu na wytrzymałość (9). Integralność mikrostrukturalna elementów betonowych jest zachowana, gdy włókna są stosowane w postaci mieszanej (10). Efektywność włókien bazaltowych w poprawie właściwości mechanicznych betonu jest potwierdzona w publikowanych pracach.…”

Section: Introductionunclassified

Experimental investigation on influence of hybrid fibers in flexural behavior of reinforced concrete beams

Vengadeshwari

Reddy

Prabhakara³

2022

Cem. Wapno Beton

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Addition of fiber is a promising solution, to enhance the flexural behaviour of reinforced cement concrete [RCC] beams. It improves the peak load, ductility and energy absorption characteristics of RCC. Ineffective mono fibers in the concrete perform very effective, when combined through the hybridization and contribute towards the strength. Fiber hybridization offers appreciable improvement in fresh and hardened properties of concrete. To achieve optimum performance, synergetic effect of fibers is more important. Incorporation of two fibers in concrete matrix, bridges the cracks effectively. Hence to investigate the effect fiber hybridization in the flexural performance, RCC beams were cast, experimented and the results were compared with the control beams. In the present study, it is intended to evaluate and compare the impact of steel and basalt fibers in mono form and hybrid form, on the flexural parameters such as first crack load, load response behaviour, ductility, crack width and flexural strength of RCC beams. To evaluate the mechanical properties of M40 grade fiber reinforced concrete, volume fractions chosen were 0.25%, 0.5% and 0.75%. Comparatively addition of basalt fibers with steel fibers, improves synergetic response to a considerable extent. From overall assessment of the mechanical properties, it was established that the combination of basalt and steel fibers at 0.25% and 0.75% respectively, produced optimum results. Optimum volume fraction of fibers identified is used in the casting of RCC beams. Wherever possible, flexural parameters were cross checked, with Indian Standards.

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“…Since it allows for the rapid erection of economical and sustainable buildings. The Pre-stressing is the technique of introducing compressive stresses of a pre-determined magnitude into a structural member to improve its behavior, to reach the full capacity of concrete in compression [1,2,3,4]. Performance of pre-stressed concrete beams under service loading conditions should be assessed to ensure their adequate serviceability over their expected life service.…”

Section: Introductionmentioning

confidence: 99%

The Behavior of Reinforced and Pre-Stressed Concrete Beams under Elevated Temperature

Badawy

Hassan

Elkady

et al. 2020

JERA

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The behavior of unbounded post tension and reinforced concrete beams under elevated temperature was presented. The experimental work was consisted of two major phases. In the first phase, the objective was studying the mechanical performance of prestressed beam, prestressed beam with steel addition and reinforced concrete beams respectively were studied. In the second phase, the residual mechanical performance of prestressed beam, prestressed beam with steel addition and reinforced concrete beams under elevated 400oC, for 120 minutes durations. The failure mechanisms, ultimate load capacity, and deflection at critical sections were monitored. The numerical prediction of the flexural behavior of the tested specimens is presented in this paper. This includes a comparison between the numerical and experimental test results according to ANSYS models. The results indicate that the prestressed beam with steel addition and reinforced concrete beams had higher resistance to beams under elevated 400oC than that of prestressed concrete beam in terms of ultimate capacity. It is also shown that the reinforced concrete beams have higher resistance to beams under elevated temperature than that of prestressed beam, prestressed beam with steel addition.

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Behavior of post-tensioned fiber concrete beams

Cited by 11 publications

References 1 publication

Fragility analysis of existing prestressed concrete bridges under traffic loads according to new Italian guidelines

Fragility analysis of existing prestressed concrete bridges under traffic loads according to new Italian guidelines

Experimental investigation on influence of hybrid fibers in flexural behavior of reinforced concrete beams

The Behavior of Reinforced and Pre-Stressed Concrete Beams under Elevated Temperature

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